The invention at hand concerns a device for radially deflecting consignments in transport plants where consignments are conveyed in linear path segments wedged between an upper and a lower belt.
In letter sorting plants, in particular in address readers, consignments up to a specific thickness of 9 mm, for example, are conveyed by means of an arrangement of cover belts, comprising a lower and an upper belt. Such a transport occurs in particular also in dynamic storage segments, where the consignments are stored mechanically following the address scanning until the reading result is supplied by the electronic reading equipment and a code corresponding to the reading result is printed onto the consignment.
A multiple deflection of the cover belt run is necessary, in particular in the storage segments to keep the space requirement low. For this, the cover belt is normally guided over large rollers, wherein the cover belt run is deflected by 180.degree. or 90.degree.. Such a plant is described in the DE 44 37 114.
In known plants, the consignments to be transported are transported standing between the upper and the lower belt, wherein the longest side of the consignment is positioned lengthwise to the transporting direction. The width of the belts is relatively narrow in relation to the maximum permissible height of the consignments to be transported (approximately 35 mm for plants with standard letter formats), so that additional guide rails are necessary to prevent a buckling of the consignments.
A further disadvantage of the narrow belts is the occurrence of carbon transfer, which damages carbon-copying papers that are transported in the consignments in such a way that the recipient cannot utilize the information transferred by the sender to the carbon-copying paper. For that reason, wider belts are used (approximately 90 mm) to be able to transport the consignments without additional guide rails and to prevent or limit carbon transfer.
With the presently known plants, a deformation in radial direction and thus a curvature on the curve inside of the consignment occurs at the deflection rollers as a result of the radial curvature of the respective consignment through the different radii of curvature for the inside and outside and the tangential shear restraint of the consignment inside by the outer edge of the letter.
When the consignment rolls off a deflection roller, this surface curvature is pressed directly against the roller or inner belt by the pressure from the outer belt, depending on the type of design. This leads to bending folds in the contact pressure area, caused by the outer belt. With a narrower belt width, these bending folds hardly interfere at all. With a wider belt width, already existing bending folds caused by preceding deflection rollers can cause the consignment to be torn up along the circulating consignment edge, thus resulting in intolerable damages. The amount of damage depends on the paper quality, the type of folding of the inserted consignments, the belt running speed, humidity etc. With wide belts, the bending folds continue to occur even in those ranges where the codes corresponding to the reading result have been printed on. As a result of this, the readability of the code can be limited or prevented.